US5250862A - Minature motor with improved bearing retainers - Google Patents

Minature motor with improved bearing retainers Download PDF

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Publication number
US5250862A
US5250862A US07/890,531 US89053192A US5250862A US 5250862 A US5250862 A US 5250862A US 89053192 A US89053192 A US 89053192A US 5250862 A US5250862 A US 5250862A
Authority
US
United States
Prior art keywords
oil
housing
impregnated bearings
face
bearing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US07/890,531
Other languages
English (en)
Inventor
Motohisa Uzawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mabuchi Motor Co Ltd
Original Assignee
Mabuchi Motor Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mabuchi Motor Co Ltd filed Critical Mabuchi Motor Co Ltd
Assigned to MABUCHI MOTOR CO., LTD. reassignment MABUCHI MOTOR CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: UZAWA, MOTOHISA
Application granted granted Critical
Publication of US5250862A publication Critical patent/US5250862A/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K5/00—Casings; Enclosures; Supports
    • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/16—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields
    • H02K5/167—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields using sliding-contact or spherical cap bearings
    • H02K5/1672—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields using sliding-contact or spherical cap bearings radially supporting the rotary shaft at both ends of the rotor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/02—Parts of sliding-contact bearings
    • F16C33/04—Brasses; Bushes; Linings
    • F16C33/06—Sliding surface mainly made of metal
    • F16C33/10—Construction relative to lubrication
    • F16C33/1025—Construction relative to lubrication with liquid, e.g. oil, as lubricant
    • F16C33/103—Construction relative to lubrication with liquid, e.g. oil, as lubricant retained in or near the bearing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/02—Parts of sliding-contact bearings
    • F16C33/04—Brasses; Bushes; Linings
    • F16C33/06—Sliding surface mainly made of metal
    • F16C33/10—Construction relative to lubrication
    • F16C33/1025—Construction relative to lubrication with liquid, e.g. oil, as lubricant
    • F16C33/103—Construction relative to lubrication with liquid, e.g. oil, as lubricant retained in or near the bearing
    • F16C33/104—Construction relative to lubrication with liquid, e.g. oil, as lubricant retained in or near the bearing in a porous body, e.g. oil impregnated sintered sleeve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C35/00—Rigid support of bearing units; Housings, e.g. caps, covers
    • F16C35/02—Rigid support of bearing units; Housings, e.g. caps, covers in the case of sliding-contact bearings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2380/00—Electrical apparatus
    • F16C2380/26—Dynamo-electric machines or combinations therewith, e.g. electro-motors and generators

Definitions

  • This is invention relates generally to a miniature motor used in power tools, household electric appliances (vacuum cleaners, etc.), for example, and more particularly to a miniature motor whose bearings retainers for holding oil-impregnated bearings are improved.
  • FIG. 1 is a longitudinal sectional view illustrating the essential part of a miniature motor to which this invention is applied.
  • reference numeral 1 refers to a housing, made of a metallic material, such as mild steel, formed into a bottomed hollow cylindrical shape and having a permanent magnet 2 formed into an arc segment shape, for example, on the inner circumferential surface thereof.
  • a rotor 5 comprising an armature 3 facing the permanent magnet 2 and a commutator 4 is provided in the housing 1.
  • numeral 6 refers to an end plate, made of the same metallic material as that of the housing 1, and formed in such a fashion as to be engaged with the opening of the housing 1.
  • Numeral 7 refers to a brush arm adapted to make sliding contact with the commutator 4 and provided on the end plate 6, together with input terminal 8 electricality connected to the brash arm 7.
  • Numerals 9 and 10 refer to oil-impregnated bearings fixedly fitted to bearing retainers It and 12 each provided on the bottom of the housing I and the end plate 6, respectively.
  • FIGS. 2 and 3 are longitudinal sectional views illustrating the essential part of an example of the bearing retainer 12 shown in FIG. 1. Like parts are indicated by like numerals in FIG. 1.
  • numeral 14 refers to a gap formed between the inside end face of the bearing retainer 12 and the end face of the oil-impregnated bearing 10.
  • FIG. 3 shows the essential part of another example of the bearing retainer 12 in which the oil-impregnated bearing 10 is positioned and held in place by bringing the end face of the oil-impregnated bearing 10 in direct contact with the inside end face of the bearing retainer 12.
  • Numeral 17 refers to a through hole.
  • FIG. 4 is a longitudinal sectional view illustrating the essential part of still another example of the bearing retainer 12 shown in FIG. 1.
  • FIG. 5 is the right-hand side view of the essential part shown in FIG. 4.
  • numeral 15 refers to a right-shaped projection provided on the inside end face of the bearing retainer 12; 16 to a ring-shaped groove formed on the outside end face of the bearing retainer 12 to form the ring-shaped projection 15.
  • the bearing retainer 12 of the conventional construction has the following problems. (The same applies to the bearing retainer 11 on the side of the housing 1.)
  • the oil-impregnated bearing 10 has a construction apt to move in the axial direction. That is, if the oil-impregnated bearing 10 is shifted to the right by an impact, vibration, etc. exerted on the end plate 6 during the rotation of the rotor 5, the gap between the commutator 4 and the oil-impregnated bearing 10 is increased, causing the shaft 13 to further protrude from the end plate 6. If the oil-impregnated bearing 10 is shifted to the left, on the other hand, the protruded length of the shaft to the right is reduced. If the protruded length of the shaft 13 deviates from a predetermined value in this way, the miniature motor cannot perform its proper functions. To cope with this problem, the oil-impregnated bearing 10 has to be press-fitted more tightly to secure it in position, or impact and vibration to the miniature motor have to be reduced to the minimum.
  • the construction shown in FIG. 3 has a problem of lubricant seeping out of the oil-impregnated bearing 10 and flowing to the outside through the through hole 17. This may prevent oil films from adequately forming on the contact surface with the shaft 13, leading to the wear of the shaft 13 and the inner circumferential surface of the oil-impregnated bearing 10, and to the seizing, or failure, of the miniature motor in extreme cases. To avoid such inconveniences, the volume of lubricant oil has to be increased by increasing the capacity of the oil-impregnated bearing 10. This may result in an increase in the size of the miniature motor. In addition, if the through hole 17 is eliminated in the aforementined construction, the contact area between the shaft 13 and the oil-impregnated bearing 10 could be reduced, deteriorating the functions of the miniature motor substantially.
  • the lubricant seeping out of the oil-impregnated bearing 10 tends to stay around the ring shaped projection 15. This may reduce the volume of lubricant fed to the contact surface between the oil-impregnated bearing 10 and the shaft 13, preventing oil films from adequately forming on the contact surface. This may pose similar inconveniences as encountered with the construction shown in FIG. 3.
  • FIG. 1 is a longitudinal sectional front view of an example of the miniature motor to which this invention is applied.
  • FIGS. 2 through 4 are longitudinal sectional views illustrating the essential part of a bearing retainer.
  • FIG. 5 is a right-hand side view of the essential part shown in FIG. 4.
  • FIGS. 6 and 7 are longitudinal sectional front and right-hand side views of an embodiment of this invention.
  • FIGS. 6 and 7 are longitudinal sectional front and right-hand side views of an embodiment of this invention. Like parts are indicated by like numerals shown in FIGS. 1 through 5.
  • numeral 18 refers to local projections provided on the inside end faces of bearing retainers 11 and 12 provided on a housing 1 and an end plate 6. The local projections 18 should preferably be provided at circumferentially equal spacings and with the same protruded length.
  • Such local projections 18 can be provided by forming recesses 19 by a punch or male die (both not shown) from the outside surfaces of the bearing retainers 11 and 12 when stamping the housing 1 and the end plate 6 from a metal sheet.
  • the oil-impregnated bearings 9 and 10 are positioned at predetermined locations and fixedly fitted to the bearing retainers 11 and 12 by placing and press-fitting the oil-impregnated bearings 9 and 10 in the bearing retainers 11 and 12 each provided on the housing 1 and the end plate 6 from the inside until the end faces thereof come in contact with the local projections 18. Consequently, the oil-impregnated bearings 9 and 10 can be fixedly fitted with the minimum required press-fitting or fastening allowances, and prevented from unwanted shifting in the axial direction. Since the local projections 18 provided on the inside end faces of the bearing retainers 11 and 12 are discontinuous in the circumferential direction, as shown in FIG. 7, there is no fear of inconveniences encountered with the ring-shaped projection 15, and lubricant can be fed smoothly.
  • the end plate 6 is made of a metallic material in this embodiment, the end plate 6 may be made of any material, such as a thermoplastic resin, and injection molding may be employed to form the end plate 6.
  • the shape and dimensions of the local projection 18 provided on the bearing retainers 11 and 12 can be freely selected.
  • the number of the local projections 18 should be at least two, or more preferably more than three.
  • This invention having the aforementioned construction and operation makes it possible to provide a miniature motor in which oil-impregnated bearings are positively and tightly held in bearing retainers, and lubricant can be fed smoothly from the oil-impregnated bearings to the shaft to ensure formation of normal oil films, and which has resistance to impact and vibration and maintains consistent quality and performance.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Power Engineering (AREA)
  • Motor Or Generator Frames (AREA)
  • Sliding-Contact Bearings (AREA)
  • Dc Machiner (AREA)
  • Motor Or Generator Current Collectors (AREA)
US07/890,531 1991-05-30 1992-05-28 Minature motor with improved bearing retainers Expired - Fee Related US5250862A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP1991039506U JPH04134152U (ja) 1991-05-30 1991-05-30 小型モータ
JP3-039506[U] 1991-05-30

Publications (1)

Publication Number Publication Date
US5250862A true US5250862A (en) 1993-10-05

Family

ID=12554933

Family Applications (1)

Application Number Title Priority Date Filing Date
US07/890,531 Expired - Fee Related US5250862A (en) 1991-05-30 1992-05-28 Minature motor with improved bearing retainers

Country Status (6)

Country Link
US (1) US5250862A (de)
EP (1) EP0516421B1 (de)
JP (1) JPH04134152U (de)
CN (1) CN2129047Y (de)
DE (1) DE69206884T2 (de)
MY (1) MY108428A (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6018206A (en) * 1997-04-14 2000-01-25 Emerson Electric Co. Method and device for inhibiting oil leakage from an electric motor
US6563245B1 (en) * 1999-09-16 2003-05-13 Aisin Seiki Kabushiki Kaisha DC brush motor
US20060070468A1 (en) * 2004-09-28 2006-04-06 Asmo Co., Ltd. Motor
US20130169090A1 (en) * 2011-12-28 2013-07-04 Tokuro Kusunoki Motor
US20140368073A1 (en) * 2010-09-20 2014-12-18 Brose Fahrzeugteile Gmbh & Co. Kg, Wurzburg Method For Producing A Housing Assembly, Housing Assembly And Ram Device
US11285586B2 (en) * 2017-08-29 2022-03-29 Panasonic Intellectual Property Management Co., Ltd. Electric power tool

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201163736Y (zh) * 2007-12-18 2008-12-10 上海鸣志电器有限公司 马达

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4006374A (en) * 1975-02-19 1977-02-01 Kabushiki Kaisha Daini Seikosha Electric micro motor for a timepiece
US4500804A (en) * 1981-10-28 1985-02-19 Mabuchi Motor Co., Ltd. Small electric motor
US4634298A (en) * 1985-08-14 1987-01-06 A. O. Smith Corporation Self-aligning bearing retention system

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4504754A (en) * 1982-09-28 1985-03-12 Universal Electric Company Electric motor
JPH069561Y2 (ja) * 1984-05-25 1994-03-09 マブチモ−タ−株式会社 小型モ−タ
JPS61189149A (ja) * 1985-02-14 1986-08-22 Matsushita Seiko Co Ltd モ−タの軸受装置
JPS62131734A (ja) * 1985-12-03 1987-06-15 Mabuchi Motor Co Ltd 自動調芯装置を備えた小型モ−タ
JPH0777502B2 (ja) * 1986-01-09 1995-08-16 マブチモーター株式会社 小型モータ

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4006374A (en) * 1975-02-19 1977-02-01 Kabushiki Kaisha Daini Seikosha Electric micro motor for a timepiece
US4500804A (en) * 1981-10-28 1985-02-19 Mabuchi Motor Co., Ltd. Small electric motor
US4634298A (en) * 1985-08-14 1987-01-06 A. O. Smith Corporation Self-aligning bearing retention system

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6018206A (en) * 1997-04-14 2000-01-25 Emerson Electric Co. Method and device for inhibiting oil leakage from an electric motor
US6563245B1 (en) * 1999-09-16 2003-05-13 Aisin Seiki Kabushiki Kaisha DC brush motor
US20060070468A1 (en) * 2004-09-28 2006-04-06 Asmo Co., Ltd. Motor
US20140368073A1 (en) * 2010-09-20 2014-12-18 Brose Fahrzeugteile Gmbh & Co. Kg, Wurzburg Method For Producing A Housing Assembly, Housing Assembly And Ram Device
US9705387B2 (en) * 2010-09-20 2017-07-11 Brose Fahrzeugteile GmbH & Co. Kommanditgesellschaft, Würzburg Method for producing a housing assembly, housing assembly and ram device
US20130169090A1 (en) * 2011-12-28 2013-07-04 Tokuro Kusunoki Motor
US11285586B2 (en) * 2017-08-29 2022-03-29 Panasonic Intellectual Property Management Co., Ltd. Electric power tool

Also Published As

Publication number Publication date
CN2129047Y (zh) 1993-03-31
DE69206884D1 (de) 1996-02-01
DE69206884T2 (de) 1996-05-30
EP0516421A2 (de) 1992-12-02
EP0516421B1 (de) 1995-12-20
MY108428A (en) 1996-09-30
JPH04134152U (ja) 1992-12-14
EP0516421A3 (de) 1994-03-30

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Legal Events

Date Code Title Description
AS Assignment

Owner name: MABUCHI MOTOR CO., LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:UZAWA, MOTOHISA;REEL/FRAME:006138/0243

Effective date: 19920413

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
FP Lapsed due to failure to pay maintenance fee

Effective date: 19971008

STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362